1. Field
The disclosed subject matter relates to probe cards for testing the performance of integrated circuits and more particularly to probe cards including nanotube probes and methods of manufacturing probe cards including nanotube probes.
2. Description of the Related Art
In the computer chip manufacturing industry, it is necessary to test the performance of integrated circuits (IC's) at various points in the manufacturing process, in order to weed out defective components and to monitor the manufacturing process. Various technologies have been employed for this purpose, though all are challenged due to the increasing demands of the IC manufacturing process.
In order to electrically test the circuitry, it is necessary to make contact with pads on the IC, i.e. to “probe” the IC. The probes must be able to align very accurately with the IC pads to be tested, and to provide sufficient current to power the IC as well as provide reliable, low resistance electrical contact at low inductance such that the test signals are not distorted. As IC manufacturing progresses to increasingly smaller geometries, increasing number of transistors, and higher clock frequencies, it challenges the abilities of existing technologies to probe the IC. The smaller geometries result in reduced test pad dimensions, which then require the probes to be better aligned to insure that they do not miss the pads. The increasing number of transistors and higher clock frequencies require that the probes be able to provide an increasing amount of current without burning up or “fusing” the probe, or reducing the probes physical characteristics such as spring force and fatigue life.
IC manufacturers increasingly desire that the IC's be tested at elevated ambient temperature to better simulate worst-case environmental conditions or to perform accelerated life testing. This places an increasing burden on the probe to be able to provide the high current levels at elevated temperatures of 150 degrees Celsius. The increased processing speed of the IC's further requires that the probes have low inductance so as not to distort the clock and signal waveforms that are fed to the IC, and to accurately transfer the waveforms from the IC to the monitoring test equipment.